A Community and Forum For Aquaponic Gardeners
First project! Any help greatly appreciated :)
Hi I'm Wes and I'm new to aquaponics. I've run a hydroponic tower vegetable garden for two years and a saltwater reef tank for a year so aquaponics seems like a good next step. If possible I'd like to do a counter top flood drain "nano" system that could go in my kitchen and grow salad greens. This diagram is what I'm thinking:
The system will be a 5 gallon fish tank with a one square foot grow bed. The tank will have a built in overflow sump with a heater and pump. The pump will run continuously to the grow bed which will have a bell siphon. The grow bed will be six inches tall and made out of wood with a pond liner. It will be lit by LEDs. I have several 3 watt LEDs leftover from my saltwater aquarium that grow corals and saltwater plants great in that tank so I'm hoping they won't have any problems growing salad greens.
Is this a realistic design? Is the size feasible? I live on a lake and I'm thinking about using gravel from the lake as aquarium substrate and grow media in the grow bed. Would that be ok or should I buy gravel instead? Any recommendations for aquarium inhabitants? Goldfish? Would this system need additional filtration besides the tank substrate and grow bed media?
I am thinking the grow bed should be filled with four inches of media and would be flooded to four inches. My guess is that the grow bed would require a gallon and a half of water to flood. Does that seem correct? Wouldn't the sump need to be almost two gallons? If that is the case would it be smarter to skip the sump and just put the pump directly in the tank? Would it make sense to flood the grow bed four times every hour to circulate at least 5 gallons an hour or would that be too much? Would this system also need airstones?
Any other thoughts or anything else I'm completely over looking?
My main goal is to have a small counter top system to grow salad greens and I have no problems completely scraping this design if there is a better way to do it. I look forward to hearing you guys' thoughts and suggestions!
Replies to This Discussion
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Permalink Reply by Vlad Jovanovic on
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At those volumes you stated I'd skip the sump...Yeah, 1'x1'x4" is 2.49 gallons and about 38-42% displacement...yeah, say a gallon and a half to flood...with goldfish though you'd be alright w/o a sump IMO...
As long as your gravel is not limestone based rocks, you should be alright (clean them off...dry them out and drop some in a glass of acid...like say vinegar. If they fizz a bunch they're no good (too much calcium carbonate i.e limestone in the rocks)...If the rocks are usable, you might want to think about boiling them as a precaution to introducing any diseases from the lake into the system...
Flooding 4 times an hour should be fine...but 4" is pretty shallow really. I mean it should work and all, just kinda shallow...
More air is never a bad idea...good luck.
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Permalink Reply by Jonathan Kadish NYC AA Chair on
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You are going to be challenged by having such a small system in that your water quality will tend to change quickly and you may not be able to manage it in time to keep your fish happy, but it can be done. As Vlad said 4 inches is shallow for plant roots, I would recommend > 6" since you are building it from scratch. I like how you are pushing the envelope with every parameter, it would be a good experiment to see how your design works. Let us know
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Permalink Reply by Wes Wilson on
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Thanks for the feedback. Great suggestions on the gravel. I will definitely see how fizzy they are with vinegar and if they don't fizz too much I'll boil them to make sure they are completely clean. I've done square foot gardens that did well with only a 6 inch deep mixture of soil/vermiculite and I'm curious how salad greens would do in 4 inches of gravel.
Vlad Jovanovic said:At those volumes you stated I'd skip the sump...Yeah, 1'x1'x4" is 2.49 gallons and about 38-42% displacement...yeah, say a gallon and a half to flood...with goldfish though you'd be alright w/o a sump IMO...
As long as your gravel is not limestone based rocks, you should be alright (clean them off...dry them out and drop some in a glass of acid...like say vinegar. If they fizz a bunch they're no good (too much calcium carbonate i.e limestone in the rocks)...If the rocks are usable, you might want to think about boiling them as a precaution to introducing any diseases from the lake into the system...
Flooding 4 times an hour should be fine...but 4" is pretty shallow really. I mean it should work and all, just kinda shallow...
More air is never a bad idea...good luck.
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I wasn't aiming to push the envelope with my first aquaponics project but may as well give it a shot for science haha. Hopefully my experience with nano reef tanks will help with managing the water quality on such a small system. I am trying to figure out how to squeeze a couple more gallons into my available space though to make it easier to stabilize everything.
A couple more questions. I am attempting to reuse as many materials from other projects as possible and minimize what I need to buy. What do you think of using painters drop instead of pond liner in the grow bed? I could double, triple, or quadruple it. Are there any other good liner substitutes? Do you guys think this setup needs any filtration in addition to the bio filtration? I'm used to filter pads, skimmers, and weekly water changes in saltwater but love the idea of not needing all of that. Also any thoughts on trying a couple fresh water prawns in this? I'm brainstorming another system around 100 gallons for prawns (and maybe catfish) but curious about options for this small setup.
Thanks again for the help! I'm finalizing the design and hoping to set this up in the next week.
Jonathan Kadish said:You are going to be challenged by having such a small system in that your water quality will tend to change quickly and you may not be able to manage it in time to keep your fish happy, but it can be done. As Vlad said 4 inches is shallow for plant roots, I would recommend > 6" since you are building it from scratch. I like how you are pushing the envelope with every parameter, it would be a good experiment to see how your design works. Let us know
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I am only familiar with canvas drop clothes, but if you tell us what type of material it is exactly, I'd be more than happy to share what little I know about different plastics. If it's any type of vinyl I'd forget about using it. Good substitutes would be LDPE, a fish safe EDPM liner, a piece of Durascrim (which is a UV stabilized virgin LDPE product with reinforced scrim...totally great stuff, but might be overkill for your situation)...Sheets of HDPE, sheets of glass, plexi-glass...since wood is porous you could try to melt paraffin carnuba, or even bees-wax into it to seal it...(the way people do with concrete tanks)...Their are plenty of good options...vinyl is NOT one of them though (even if it is touted as safe for potable water, I still would not use vinyl)...
Whether you need additional filtration depends on how many goldfish or whatever you cram in. Your probably only good for about 50 grams of fish in there. Doesn't really take much to grow most greens though. Most people kinda seem to overstock their systems. So you may have to play around a bit. There are other ways to get nitrates and plant essential elements in there without more fish...Sticking a small handful of worm castings in a woman's nylon sock is just one of them.
Prawns are pretty territorial from what I hear, and like to play "last man standing", so you might want to look into that a bit. I haven't grown them myself, so I don't know much about that.
It'll be interesting to see what you do with this nano-system and how it works out.
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Since your grow bed will be so small why don't you just use a tub of some sort? Any kind of storage tub you have around the house with a bulkhead fitting for your plumbing.
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Vlad the drop I already have was just a cheap drop cloth from Big Lots so it is probably a good idea if I go with something else. I like your beeswax seal suggestion since this is so small and I think it would look good. Sounds like a wait and see approach is best for adding additional filtration. I may hold off on the prawns until I get a much larger system setup. Thanks for your continued help and for baring with me through my newbie questions!
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Jonathan, good idea on the tub. That would be a very easy solution if I can find something close enough to the size I want. Thanks for the input.
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I'm on the fence about adding an additional container or containers to this design to bump up the total volume a little bit. This is going on a counter top beneath a cabinet and I'm tempted to squeeze 3 to 5 more gallons above it in the cabinet. In the pros column I really like the idea of having another container hidden in the cabinet. That lets me keep a clean compact look on the counter top but still add a few more gallons to the total system and essentially gives me a hidden sump where I can later tweak things. On the other hand I would also like to keep this system as simple as possible with the hope that if it does end up working it would be cheap and easy for another aquaponics beginner to give it a shot. Adding a hidden container above the grow bed definitely makes it a bit more complicated. What do you guys think? Use the extra hidden space to bump up total system volume or keep it simple with just the grow bed and tank?
There is another thing that has been bothering me about this system... the water level in the tank is going to be fluctuating a lot. If I stick with the current bell siphon design every 15 minutes the tank will slowly be lowering 20% to 40% (1 to 2 gallons) as the grow bed floods and then quickly regaining that volume as the grow bed drains. I know reef tanks can handle this a bit as corals are used to low tides but I wouldn't do that to my reef tank every 15 minutes. Would this affect the freshwater inhabitants very much? I'm brainstorming ways around this without changing the design very much but I feel like my ideas would over complicate things. The simplest thing I can think of would be to have a drain and a bell siphon and have the drain close on a timer for like an hour two times a day. That way the tank would have a stable volume for 22 hours a day with the grow bed constantly being irrigated during that time and then for the other two hours a day the tank would have the fluctuating volume while the grow bed floods and drains eight times. Thoughts or other ideas? Am I over thinking this? Thanks!
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Permalink Reply by RupertofOZ on
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If you're worried about the tank fluctuating Wes... and as you seem to be leaning towards a timer anyway...
Then ditch the idea of a siphon... and just go with a standard overflow standpipe.. ala timed flood & drain...
(I don't understand peoples obessions with siphons in general... but used with a timer is just a nonsense IMO)
An overflow stand pipe... has two small 6mm holes drilled at the base of the stnadpipe...
So water begins returning to the fish tank as soon as the flood begins... lessening the tank fluctuation...
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RupertofOZ that is a good point and that would greatly slow the fluctuation. It looks like without adding additional water reservoirs there is no way around the tank's water volume dropping 20% to 40% every flood cycle if I use a flood drain system and a squarefoot grow bed flooded to 4 inches.
As an alternative I've researched continuous flow a little. Some people seem to think continuous flow works great on shallow grow beds and others still argue that flood drain works much better.
Now I'm thinking about dividing the grow bed as an experiment to see which method works best in this setting. I'm tempted to divide it into quarters to try four different methods. What do you guys think? One flood drain section with a bell siphon, one section with constant flow, a NFT section, and a raft section? Possibly have the constant flow section drain into the NFT section and have the flood drain section drain into the raft section for filtration? Due to the size I'm thinking one plant per section. Four salad green plants should be pretty good for a kitchen setup.
I'm going to ditch the idea of using gravel from the lake on this project since it already has enough experimental elements. Plus I'm thinking the gravel may have some limestone since this is Limestone County :) Any media suggestions for this setup? Is this aquarium gravel fine for the tank and the grow bed?
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But Rupert... siphons are just cool and drains are boring ;)
RupertofOZ said:If you're worried about the tank fluctuating Wes... and as you seem to be leaning towards a timer anyway...
Then ditch the idea of a siphon... and just go with a standard overflow standpipe.. ala timed flood & drain...
(I don't understand peoples obessions with siphons in general... but used with a timer is just a nonsense IMO)
An overflow stand pipe... has two small 6mm holes drilled at the base of the stnadpipe...
So water begins returning to the fish tank as soon as the flood begins... lessening the tank fluctuation...
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